Citation

Martin AE, Gregg RD. IEEE Trans. Robot. 2016; 32(4): 943-948.

Affiliation

Departments of Bioengineering and Mechanical Engineering, University of Texas at Dallas, Dallas, TX, 75080 USA, rgregg@utdallas.edu.

Copyright

(Copyright © 2016, Institute of Electrical and Electronics Engineers)

DOI

10.1109/TRO.2016.2572687

PMID

28082836

Abstract

Predictive simulations of human walking could be used to investigate a wide range of questions. Promising moderately complex models have been developed using the robotics control technique hybrid zero dynamics (HZD). Existing simulations of human walking only consider the mean motion, so they cannot be used to investigate fall risk, which is correlated with variability. This work determines how to incorporate human-like variability into an HZD-based healthy human model to generate a more realistic gait. The key challenge is determining how to combine the existing mathematical description of variability with the dynamic model so that the biped is still able to walk without falling. To do so, the commanded motion is augmented with a sinusoidal variability function and a polynomial correction function. The variability function captures the variation in joint angles while the correction function prevents the variability function from growing uncontrollably. The necessity of the correction function and the improvements with a reduction of stance ankle variability are demonstrated via simulations. The variability in temporal measures is shown to be similar to experimental values.

Language: en

Keywords

Biomimetics; human locomotion; legged robots; motion control; variability